1. Field of the Invention
The present invention relates to a networking device for exchanging data frames. In particular, the device exchanges data between a WAN and one or more LAN segments.
2. Description of the Related Technology
A residential gateway is well known in the art. Residential gateways are common devices used in home networking. They provide bridging and routing functions between on the one hand a public Wide Area Network (WAN) infrastructure such as the Internet, and on the other hand a Local Area Network (LAN). The LAN is essentially an in-house network, and typically contains a wired Ethernet-based segment and/or a wireless WiFi-based segment.
When multiple LAN segments are present, packets entering the residential gateway from the WAN side are forwarded to the respective LAN segments by application of standard bridging and/or routing rules. These rules take into account the destination address (MAC address or IP address and/or TCP/UDP port number) of the incoming packets to determine the outbound port. Additionally, the optional Virtual LAN Identifier (VID), if present, may be used to refine the forwarding decision. These very rudimentary classification rules are stored in a forwarding information base (routing table, bridging table, VLAN membership map, . . . ).
Once an outbound port has been selected, quality of service (QoS) related header fields such as the IP differentiated services code point (DSCP) field, may be checked against a set of QoS rules to determine the queue to which the packet shall be written. This behavior is common in existing devices, as may be evidenced by way of example by the operating manual of the Adtran NetVanta products (Adtran AOS QoS Configuration Guide, 61200860L1-29.3E, March 2006, available on-line (accessed 2007 Apr. 5) at URL http://www.adtran.com/adtranpx/Doc/0/DVA89BJ6DKAKR25MCQM8BGVD75/61200860 L1-29.3E.pdf).
More sophisticated ways of classifying incoming packets are known in the art. The classifier may take into account information about source and/or destination, as stored in the incoming packet, to determine the “flow” to which the incoming packet belongs. This “flow” represents a certain application or service, and subsequent manipulations such as forwarding, tagging, and encapsulating, may be based on the identified flow to present application-aware behavior.
A basic form of flow processing is used for demultiplexing “conversations” over the physical segments that make up an aggregated link in Ethernet's link aggregation. A residential gateway using conversations to demultiplex data traffic over interfaces with different transmission profiles is disclosed in patent application EP 1328091A, where it suffices to read the term “residential gateway” for the more general term “modem system”.
Even more advanced classification schemes are known in the art for a router as in WO 2004/080024A and for an access node (for example, patent application EP1662718A). Obviously, such classification schemes could also be used in a residential gateway.
It is noted that residential users often use pre-existing cabling infrastructure to deploy point-to-point or point-to-multipoint links between devices that are capable of interacting with each other. Industry standards exist for the use of in-house telephone wiring (e.g., HomePNA (HPNA), denoting Home Phoneline Networking Association) or coaxial television wiring (e.g., MoCA—Multimedia over Coax Alliance) for this purpose. These non-native networks are cumbersome to install and maintain. As they poorly interact with dedicated LAN equipment, the result is a sub-optimal patchwork of network segments.
By their nature, the different segments of the patchwork network are more or less suited for different services. Local Area Networks offering different services over different physical interfaces of the same device are well known in the art; this paradigm is sometimes referred to as “colored interfaces” (Beck M., “Ethernet in the First Mile: the IEEE802.3ah EFM Standard.”, 1st edition, NY: McGraw-Hill Professional, 2005, p. 86-87).